Not a laugh, but why laughing helps you stay strong.
I often point out that one of the reasons I married David is that he keeps me laughing. One of the reasons we have stayed married is that we make lots of room for laughter in our lives. It gets us beyond the times we want to kill each other. We have developed some running jokes that poke fun at ourselves and make others laugh. Maybe, couples should go to clown school together instead of marriage counseling.
Caution: The best laughter and the most strengthening is not cruel laughter, not aimed at individuals, but laughter at the universe, our place in this world, and ourselves. Stay strong.